MCPA-isopropyl is made by first producing technical-grade MCPA acid through the standard sequence of para-cresol chlorination and subsequent carboxylation to form the phenoxyacetic acid. The purified acid is then esterified with isopropanol in the presence of an acid catalyst, with the reaction typically run under reflux while removing water to push the equilibrium toward ester formation. After completion, the mixture is neutralised and washed to eliminate residual catalyst and unreacted alcohol, and the crude ester is refined, often by vacuum distillation, to meet technical specifications.
